SQL for Data Analysts PCAD-31 Practice Questions (Page 1)

Questions 1–5

1. 1foundation · easy

   Which SQL function is used to count the number of rows in a result set?

   • AAVG()
   • BCOUNT()
   • CMAX()
   • DSUM()
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2. 2application · medium

   A data analyst needs to retrieve the average salary of employees in each department from a SQLite database. The tables are `employees(id, name, salary, dept_id)` and `departments(dept_id, dept_name)`. The analyst wants to include departments with no employees (showing NULL average). Which type of JOIN should the analyst use?

   • ARIGHT JOIN
   • BFULL OUTER JOIN
   • CLEFT JOIN
   • DINNER JOIN
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4. 3foundation · easy

   What is SQL injection?

   • AA tool for database backup.
   • BA technique where malicious SQL code is inserted into a query.
   • CA way to encrypt data in a database.
   • DA method to speed up database queries.
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5. 4application · easy

   A Python developer is writing a script to connect to a SQLite database and execute a query that returns a single value (e.g., the count of rows in a table). Which method should the developer use to fetch the result?

   • Acursor.fetchall()
   • Bcursor.fetchmany(1)
   • Ccursor.fetchval()
   • Dcursor.fetchone()
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6. 5foundation · easy

   What is the purpose of the connect() function in the sqlite3 module?

   • AIt establishes a connection to a database file.
   • BIt creates a new table in the database.
   • CIt closes the database connection.
   • DIt executes a SQL query.
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